Malate-based polyester chemically shielded metal-phenolic networks coated artificial hair fibers with long-lasting antimicrobial and anti-inflammatory performance

Microbially induced peri-implant infection and dislodgement are among the most common complications of implant surgery. Most existing medical implant surfaces lack long-lasting antimicrobial capacity and are adversely affected by excessive reactive oxygen species production or burst release of antimicrobial agents within short periods. This study aimed to perform in situ reduction and anchoring of silver nanoparticles (AgNPs) on polyamide (PA) surfaces pre-deposited with tannic acid (TA) coating and the multicycle deposition of tannin-sliver (TA-Ag) metal-phenolic networks (MPNs). Through in situ reduction of silver ions (Ag+) by plant-derived tannic acid, TA-Ag MPNs were deposited on polyamide in a multicycle manner, and the remaining functionalities on the immobilized TA moieties were subsequently covalently linked to poly(1,8-octanediol L-malate) (POM), a malate-based biodegradable polymer. The AgNPs were effectively locked in the coating matrix comprising MPNs and POM via coordination bonds between AgNPs and tannin and covalent crosslinks between tannin and POM, which slowed down the "burst release" of AgNPs and extended the release time of Ag+ (up to 56 days). The remarkable long-term antibacterial (>97 %) and anti-inflammatory coating have promising widespread applications not only in artificial hair fibers but also in other medical implant applications.